1. Field of the Invention
The invention relates to an antitheft protection system for a motor vehicle, in particular to a steering/ignition lock. The system includes a key with an energy-receiving unit and a data-transmitting unit, and a lock with an energy-transmitting unit and a data-receiving unit. The data-receiving unit is connected to an evaluation unit which checks the received data for their authorization and releases a locking element after the entry authorization has been verified.
2. Description of the Related Art
A prior art antitheft protection system (German published non-prosecuted patent application DE 44 34 587 A1) has an ignition key which is inserted into an ignition lock. The insertion causes energy to be transmitted from the lock to the key. In response, the key generates a code signal and transmits it back to the lock. The code signal is evaluated and an immobilizer is disengaged if the authorization is verified.
Moreover, an electromagnetic lock is unlocked, as a result of which the key can be turned in the lock. The steering wheel lock is mechanically disengaged by turning the key.
In that antitheft protection system, the code signal is transmitted from the key to the lock by means of IR radiation. An optical fiber is arranged in the lock which guides the code signal to a more remote IR receiver. The mounting of the optical fiber is very complicated and, moreover, the optical fiber is susceptible to mechanical stress.
Another antitheft protection system for a motor vehicle has a key which transmits IR signals to a lock. However, in that case the lock is not the ignition lock but a receptacle on whose rear end an IR receiver is arranged. With the key inserted, the IR transmitter of the key is arranged close to the IR receiver of the lock. A coil is arranged around the lock by means of which energy is transmitted from the lock to the key so that the code signal can be triggered. There, as well, the lock is very complicated in its construction, since the coil is wound around the lock. Furthermore, the magnetic coupling between the coil of the lock and the coil of the key is quite limited.
It is accordingly an object of the invention to provide an antitheft protection system for a motor vehicle, which overcomes the above-mentioned disadvantages of the prior art devices and methods of this general type and which is of simple design and by means of which it is possible effectively to transmit both energy and data from a lock to a key, or vice versa.
With the foregoing and other objects in view there is provided, in accordance with the invention, an antitheft protection system for a motor vehicle, comprising:
a key having an energy-receiving unit and a data-transmitting unit;
a lock having an energy-transmitting unit and a data-receiving unit, an evaluation unit connected to the data-receiving unit for checking a data signal received by the data-receiving unit with regard to an authorization and for releasing a locking element if the authorization can be verified;
the energy-transmitting unit and the data-receiving unit of the lock being constructed as a single component disposed substantially centrally in the lock; and
the key having an end carrying the energy-receiving unit and the data-transmitting unit of the key, the end being adapted to be inserted into the lock, whereby the energy-receiving unit and the data-transmitting unit of the key, and the energy-transmitting unit and the data-receiving unit of the lock are disposed in close proximity to one another and approximately aligned with one another.
In other words, a transmitting and receiving unit is constructed in the lock as a single component by means of which energy can be inductively emitted and data can be received by the key. The transmitting and receiving unit is arranged in this case in the middle of the lock, with the result that with the key inserted the transmitting and receiving unit of the lock and a transmitting and receiving unit of the key are arranged close to one another.
In accordance with an added feature of the invention, a data-receiving unit is disposed in the key, and a data-transmitting unit is disposed in the lock, and wherein the data-receiving unit in the key and the data-transmitting unit in the lock, together with the data-transmitting unit of the key and the data-receiving unit in the lock, are adapted to carrying out bidirectional data transmission between the key and the lock.
In accordance with an additional feature of the invention, the data-transmitting unit in the lock and the energy-transmitting unit and the data-receiving unit are constructed as a single component.
In accordance with a further feature of the invention, the locking element is an electromagnetic locking element for selectively locking and releasing a steering lock and/or for selectively engaging and disengaging an immobilizer of a motor vehicle.
In accordance with again another feature of the invention, the lock is an ignition lock and the key is an electronic ignition key of a motor vehicle.
In accordance with a concomitant feature of the invention, the energy-transmitting unit and the energy-receiving unit each are a coil, the data-transmitting units are phototransistors, and the data-receiving units are IR diodes.
Thus, bidirectional data communication can take place using the antitheft protection system if the lock transmits not only energy signals but also data signals. For this purpose, the lock has a data-transmitting unit which is also integrated in the component. A steering-wheel lock of the motor vehicle is disengaged not mechanically but via an electromagnetic blocking device by means of a code signal. In this case, the lock is a steering lock or ignition lock and the key is an electronic ignition key. The transmitting and receiving unit is constructed as an optotransmitter and optoreceiver for the purpose of reliable data transmission. The lock and the key each have a coil for the purpose of inductive energy transmission.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an antitheft protection system for a motor vehicle, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.